Lifting jack



J. C. KOPF.

LIFTING JACK.

APPLICATION- FILED JULY 27, 1920.

Reissue-a Nov. 23, 1920.

2 SHEETSSHEET I.

j. C. KOPF.

.LIFTING TACK.

APPLICATlUN FILED JULY 27, 1920- Reissu'ed Nov. 23, 1920.

2 SHEE lS-SHEET 17 Q 1 w i" I If T i a /18 12 l I 5 A TTORNE Original No. 1,321,456, dated UNIE'ITED srA Es PATENT; oF-llcs;

m c. KOPF, or BELLEVUE BOROUGH, PENNSYLVANIA, Assreiwoa TO TH DUFF MANUFACTURING COMPANY, or PITTSBURGH, PENNSYLVANIA, A COMO-Rb TION OF PENNSYLVANIA;

To all whom it may concern:-

borough of Bellevue, in the county of Allegheny and State-f Pennsylvania, have invented a new and useful Improvement in Lifting-Jacks, of which the followlng is'a' full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in-

which u Figure 1 is a developed vertical'section of a lifting jack embodying my invention, the general planeof the section being on the line "I- I of F ig; 2;: Fig.2 is a horizontal section on the. irregular line IIII of Fig. 1; Fig. 3 is aperspective view of the clutch barrel and its brake band;'Fig; 4 is a detail sectional view showing one of the friction clutch disks and its engagement with its shaft; and Fig. 5 is a plan view showing one of the cooperating friction clutch disks.

My invention has relation to lifting jacks and more particularlytohigh-speed or selflowering screw-jacks. I v r One vof the, objects of my invention is-to provide a jack of this type having mechanism of simple, compact, strong, and effective character, wherein the action of the load on the jack is caused to automatically lock the jack against undesired descent. I

A further object is .tofprovide locking means of this characterin-which the locking action is directlyproportional to the load on the jack, so that such action increases as the load increases, and the lockis" capable of. Y acting as a cushion for stopping-whereby a high degree of safety isaiforded'in the operation of these jacks.

A still further object is toprovide manual means in connection], with the locking means,

' whereby the jack may bef rapidly operated when unloaded and whereby, also," the jack can be lowered fin-fa loadedcondition by. manualefi'ort exerted against a'constantly applied "holding resistance;

In the particular embodiment, a multipledisk device is'subject to the end-thrust of a worm, of such pitch as to'bedriven by. a

worm-wheel, which in turn has connection with a quick-pitch lifting screw, so that the action of the load is transmitted to compact and lock the-flat surfaces of the multipledisk device, which are capable of slippage of a beneficial nature,-as in' arresting the ering jacks.

preferred emb LIFTING-J'ACK.

momentum of lowering, or in case of manual rotation of the worm by a crank, which is preferably provided. An important feature and general 'ObJGCt, therefore, has to do'with the employment of such adeVice for the holding, lowering and stopping of self-low- The' nature of understood by ing drawings,

in which I have shown the odlment thereof andwhich will now be described, I however, that various changes can be made arrangement of the parts, without departng from the spirit and scope of my inventlon as definedin theappended claims.

In these drawings, n'ates the baseof the jack having an upwardly projecting cylindrical column 3, in whlch ls secured thelint'ernally threaded nut 4. 5 designates the screw of the jack, which my invention will be best reference to the accompany-- the numeral 2 .desig 1920. November 1;, -1919,'Seria1 No.- 284,318, filed March 22, 1919. Application fo reissue filed July 27, 1920. Serial No. 399,407. v

it being premised,

in the details of construction and general extends through the nut 4 and downwardly 1n thecolumn 3. Surrounding the column 3 is a lifting shell 6, having secured to its upper end the casing 7, in. which the operating parts presently to be described are mounted, and which carries at its upper end a lifting plate' 8" to receive the load; This plate is provided with ball bearings at 9. Extend-.

ing through a suitable hearing 10 in the side of the-caslng is an actuating stub shaft 11,

adapted to receive the usual operating lever (not shown).

screw 5.

.Asthus far described, the parts are, in-

general, of well knownch'aracter' andforni no part of my present inventionexcept 1n spondingly forme jc utch' face of a second clutch member 16, which is 'looselymounted on the screw 5, just above the thread thereof. The clutch 'member 16 is formed on its ,peripher with worm-wheel teeth 17,- which. en 'age t e-threads of a worm '18, secured to a orizontal Sh'aft, 19 -mounted in suitable At it s; inner end, said shaft CaIIIGS- the beveledQpinion 12, whose teeth mesh with the horizontal .beveled gear 13,-

' which is keyed to the upper portion 'ofthe combination. 1% designates a clutch mem 9 'bearingsin the casing 7. This Shaft 19 is extended throu h the casing atone end and Q is provided with a hand crank 20. This intercalating disks'22, which are engaged on shaft 19 is also provided with a multiple disk friction clutch device comprismg one set of flat-faced friction elements, or clutch disks, 21, which are engaged with the shaft 19 to rotatethere'with, and anotherset'of their peripheries with a barrel 23. These 'interjacent friction elements are disposed at the end-thrust thereof under load, against one end of the worm 18, to be compacted by the support of the side 'wallof the casing. Said barrel has a cylindrical outer surface which, is surrounded by a friction brake band one end of this band being connected .to' a fixed pin 25, and the other end .to a rod 26, whose end is connected to a lever 27, having acam or eccentric portion .28, which bears against the casing 7. spring 29 is arranged to act on the rod 26.

The threads on the screw 5 and also the threads on, the worm 18, are of relatively quick pitch, so that said screws will readily rotate under theaction of a load on the jack Theoperation is as follows:.v

The screw andthe lifting head or plate 8 can be quickly run up to the load by turning the crank 20 and thereby turning the screw through the action of the worm 18 and worm wheel 16,.the clutch faces of the members 14 and 16 engaging to cause said membersto rotate together and thereby turn the screw. In this operation it'is' not. necessary to releasethe lock or to set it again when the load is reached, because with no load upon the jack the frictional resistance between the members 21, 22 is inconsequen tial. The shaft 11 is' then actuated by its leverflin the 'usuallmanner to further raise 'the screw and lift the loads g In the intervals of lifting, and whenthe load has been raised to the desired height,"

the jack is automatically locked against running down by the action ofthe load transmitted from the screw through the WOI'III',

wheel to the quick-lpitch' worm, producing an .end-thrust on t e tionally to ther, so that the worm cannot be turned y the load, the disks 22 being held absolutely by the gripoflthe brake 24 on the barrel 23. .The extent of the frictional action-ofthe clutch is directly prortional to the loadon the screw, increas- 1 1n' asthe load increases en-it is desired to lower the load, the

lever 27 is turned from the position shown 1 in Fig. 1, to a position iny which the higher port-Ion of its :cam or'eccentric' bears on the casing :;.:This causes an endwise movement or the maze and releases the brake band Ihe barrel 23 is'now free to turn, and

dut bra e or slippage connection, wherein the latter causing it to. move e'ndwi'se slightly and applying press sure to the disks which locks them fricmay be either quickly :or gradua o any desired extent whenever necessary and whereby the jack may be, operated the entire friction clutch device including apply the brake In this operationmo- .mentum will cause the flat faces of thedisks 21 to slip somewhat on-thefaces of the members 22, before coming to rest, so that the shock of arrestin the moving weight is softened. u This is lmportant, both as a means of saving the mechanism and to with self-lowerin jacks, designed for heavy The .clutc thus acts as a cushion slippage is overcome and the load brought to're'st by the action of the load itself; so that a prompt but not abrupt stopping is produced. In this connection it will be understood that the heavier the load, the greater will be the momentum, but the greater also the end-thrust, and consequently aslong as the friction faces possess a sufiicient excess of surface for holding, the slippage can be only of a useful a character, and slight inextent.

- Also, the friction clutch device may be left in and the lowering controlled by the crank 20. In such case the manual efi'ort has merely to overcome, the excess frictionbetween the disks, causing the disks21 to rotate between the stationary disks 22, without, however, removing the pressure; conseuently the jack can descend no faster than" t e manual'opera tion of the crank permits,

avoid the accidents which have occurred and, notwithstandingthat the worm is ofv I quick pitch, the operator sustainsnone of the load, and the constantly acting braking effect of the multiple diskdevice will hold the loadtas soon as he ceases to turn the. crank.- In this' nanner, the jack can .be low ered to any desired extent, and stopped-in the exact desired position.v

The advantages of my in entionwill beapparent to'those familiar with jacks of this .ty'pe, since it provides a high-speed jack capable of. handling large loads with per-' fect safety, the locking action against accidental lowering of the load increasing as :the load increases. Atlthe same time, the

invention provides, means whereby the vload l y lowered quickly in the absence of load.

, The method .of construction and mode of" operation issimple, and-the parts thereof s are strong and of durable character. The

directassociation of the load-appliedlock subject to the end-thrus'to ally operated control means for causing the r and its manual control means, with the quick-pitch worm, upon the one shaft or axis, is a feature of important-simplicity,

making for economy, compactness, durabilit and reliable action.

T e overrunning clutch 14, 15. makes it unnecessary for the worm gearing l6, l8

.and parts connected with the worm tobe driven from the screw in the load-lifting operation, but this is not essential to theoperation as in any event the pressure is removedfrom the disks at such time.

I claim: 1. A jack havinga lifting screw adapted to be rotated by the actionof the load, and means for actuating the screw to .lift the -;load, in combination with a worm-wheel. having connection with the screw, a worm meshing the worm-wheel. and adapted to be i driven thereby, and acushion-slippage look ing device subjectto the end-thrustof the worm.

,2. A jack having a liftingscrew adapted to be rotated byf the action of the load, and

' means for actuating the screw to. lift the loa'd, incombination with a worm-wheel having connection with the s.crew,.a worm meshing the worm-wheel and adapted to be driven thereby, a manually-operated brake, and a cushion-slippage connection between the brake and the ,worm subject to the end-thrust of th e.wo rm= 3; A jack having a lifting screw adapted to be rotatediby the action of the load, and

meansfor actuating the screw to lift the load, in combination with a worm-wheel having connection-with the screw, a worm meshing the worni-wheel and adapted to be driven thereby, a cushion-slippage locking device the worm, manuworm to ,beheld'or released, and manually operated means for rotating the'worm.

' 4., A jack havingv alifting screw'adapte'd to be rotated-by the action of the-load, and

" means for actuating the screw toli-ft the load, in combination with a worm-wheel having connection withthe screw, a worm meshing the worm-wheeland adapted to be driven thereby, a manually-operated brake,

a cushion-slippage connection between the brake and the worm subject to the end-thrust of the worm, and manually operated means for rotating the worm. Y I 5. A jack having a lifting screw adapted to be rotated by the action of the load, and

means forjactuating the screw to liftfthe 7 load, in combination with a worm-wheel having connect on with. the screw, a worm meshing the worm-wheel and 'adaptedto' be driven thereby, a locking'device' comprising I frictional slippa e members adapted .tobe

locked together "in 'holdin relation to theload'by the end-thrust-o theworm, and

one part of the clutch.

manually operated means for rotating the worm with said members in contact.

6. A jack having a lifting screw adapted to be rotated by the action of the load, and

means for actuating ,the screw to lift the load, in combination with a worm-wheel having connection with the screw, aworm meshing the worm-wheel andadaptedto. be driven thereby, and locking means comprising. flatfaced friction elements adapted to be locked together in holding relation to the load by theend-thrust of the worm.

7. A ja'ck having a lifting-screw adapted to be rotated by the action of the load, and means for actuating the screw to lift the load, in combination witha wormj-wheelhaving connection with the screw, a worm meshi'ngthe worm-wheel and adapted to be driven thereby, and a multiple friction disk device subject'to the end-thrust of the worm.

8. A jack having a lifting screw adapted to be rotated by the action'of the load, and means for actuating the screw to lift the load, in combination with aworm-wheel hav--- ing connection with the screw, a worm meshing the worm-wheel and adapted to be driven thereby, a multiple friction disk device subject to the end-thrust of the worm, and manually operated 'controlmeans'opera'tive upon one part of said device. 5

9. A jack having a lifting screw adapted to be rotated by the action of the load, and means for actuating the screw to lift the load, incombination with a'worm-wheel j havlng connection with the-screw, a worm meshing the worm-wheel and adapted to be "driven thereby, a multiple friction disk clutch subject to the end-thrust of the worm,

and a manually operated brake related to 10. jack having a lifting screw adapted to be rotated'by the action ofthe load, and

means for actuating the screwto lift the load, in combination with a worm-wheelhaving connection with th'e screw, 'a-worm meshing the worm-wheel. and 'adaptedto be driven thereby, a multiple friction disklock subject to the'end-thrust of the worm,

andmanual means for rotating the worm.

. 1 1. A jack having a lifting screw adapted to berotated by the action of the load, and

means for actuating the same tolift the load, a worm-wheel having connection with. the

screw, and a worm and worm-shaft, the

worm meshing the worm-wheeland adapted to be driven thereby, a barrel surrounding connected to the barrel,- a coiiperati'ng set of friction members connected tothe shaft, and

means whereby the"barrel maybe held against movement or may be free to turn with'the worm shafti 12. 'A jack having a lifting screwadapted -to be rotated by the action ofthe load, and

1.20 i the worm-shaft, afset of friction members 7 i means for actuating the same to lift the load, a worm-wheel havin connection with the screw, and awo'rm and worm-shaft, the worm'rneshing the worm-wheel and adapted to be driven thereby, a multiple-disk-friction device on the worm shaft comprising a bar- -rel and two sets of friction members connect.-

ed to the barrel and shaft, respectively, and a brake cooperatingwith the barrel.

[13. In a jack, the combination witha vertically movable load member, and mechanism adapted to run down under the load- 1 and including a worm-wheel having connection with the load-member and a worm adapted'to be driven'by said worm-wheel, of

a lockvcomposed"ofIflat-faced friction elements adapted to be compacted by endthrust of the worm.

14. A jack having a lifting screw adapted to be rotated by the action of the load, and means for actuating the screw to lift the load, a worm-wheel having connection with the screw and .a worm meshing the wormwheel and adapted to be driven thereby, a friction locking device subject to the endthrust of the worm, and manually operated control means cooperating with said device for causing the worm to be held or released, said worm, locking device and, control means being associated upon the one axis.

15. A jack having a lifting screw adapted to be rotated by the action of the load, and

means for actuating the screw to lift the load, a worm-wheel having connection with the screw and a worm meshing the wormwheel and adapted to be driven thereby, a

friction clutch subject to the end-thrust of the worm, and a brake cooperating directly" with the clutch.

16. A lifting jack having a liftingscrew adapted'to be rotated by the action of the.

load, means for actuating saidsc'rew to raise the load, a two-part overrunning, clutch, one

member of which is mounted to rotate with .the screw and the other member of'which is looselymounted with respect to the screw, the last-named member having worm-teeth thereon, a quick-pitch worm -meshing the teeth of said membeig'and frictional locking means subject to the end-thrust of the worm.

JOHN C. KOPF. 

